BackgroundSpeaking up is important for patient safety, but often, health care professionals hesitate to voice concerns. Understanding the influencing factors can help to improve speaking-up behaviour and team communication. This review focused on health care professionals’ speaking-up behaviour for patient safety and aimed at (1) assessing the effectiveness of speaking up, (2) evaluating the effectiveness of speaking-up training, (3) identifying the factors influencing speaking-up behaviour, and (4) developing a model for speaking-up behaviour.MethodsFive databases (PubMed, MEDLINE, CINAHL, Web of Science, and the Cochrane Library) were searched for English articles describing health care professionals’ speaking-up behaviour as well as those evaluating the relationship between speaking up and patient safety. Influencing factors were identified and then integrated into a model of voicing behaviour.ResultsIn total, 26 studies were identified in 27 articles. Some indicated that hesitancy to speak up can be an important contributing factor in communication errors and that training can improve speaking-up behaviour. Many influencing factors were found: (1) the motivation to speak up, such as the perceived risk for patients, and the ambiguity or clarity of the clinical situation; (2) contextual factors, such as hospital administrative support, interdisciplinary policy-making, team work and relationship between other team members, and attitude of leaders/superiors; (3) individual factors, such as job satisfaction, responsibility toward patients, responsibility as professionals, confidence based on experience, communication skills, and educational background; (4) the perceived efficacy of speaking up, such as lack of impact and personal control; (5) the perceived safety of speaking up, such as fear for the responses of others and conflict and concerns over appearing incompetent; and (6) tactics and targets, such as collecting facts, showing positive intent, and selecting the person who has spoken up.ConclusionsHesitancy to speak up can be an important contributing factor to communication errors. Our model helps us to understand how health care professionals think about voicing their concerns. Further research is required to investigate the relative importance of different factors.

MDC9, also known as meltrin gamma, is a membrane-anchored metalloprotease. MDC9 contains several distinct protein domains: a signal sequence followed by a prodomain and a domain showing sequence similarity to snake venom metalloproteases, a disintegrin-like domain, a cysteine-rich region, an epidermal-growth-factor-like repeat, a transmembrane domain and a cytoplasmic domain. Here we demonstrate that MDC9 expressed in COS cells is cleaved between the prodomain and the metalloprotease domain. Further, when MDC9 was co-expressed in COS cells with amyloid precursor protein (APP695) and treated with phorbol ester, APP695 was digested exclusively at the alpha-secretory site in MDC9-expressing cells. When an artificial alpha-secretory site mutant was also co-expressed with MDC9 and treated with phorbol ester, APP secreted by alpha-secretase was not increased in conditional medium. Inhibition of MDC9 by a hydroxamate-based metalloprotease inhibitor, SI-27, enhanced beta-secretase cleavage. These results suggest that MDC9 has an alpha-secretase-like activity and is activated by phorbol ester.

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MDC9, also known as meltrin gamma, is a membrane-anchored metalloprotease. MDC9 contains several distinct protein domains: a signal sequence followed by a prodomain and a domain showing sequence similarity to snake venom metalloproteases, a disintegrin-like domain, a cysteine-rich region, an epidermal-growth-factor-like repeat, a transmembrane domain and a cytoplasmic domain. Here we demonstrate that MDC9 expressed in COS cells is cleaved between the prodomain and the metalloprotease domain. Further, when MDC9 was co-expressed in COS cells with amyloid precursor protein (APP695) and treated with phorbol ester, APP695 was digested exclusively at the alpha-secretory site in MDC9-expressing cells. When an artificial alpha-secretory site mutant was also co-expressed with MDC9 and treated with phorbol ester, APP secreted by alpha-secretase was not increased in conditional medium. Inhibition of MDC9 by a hydroxamate-based metalloprotease inhibitor, SI-27, enhanced beta-secretase cleavage. These results suggest that MDC9 has an alpha-secretase-like activity and is activated by phorbol ester.